Multifunctional yarns are required for diverse applications, like clothing that protects emergency responders and provides sensing, communication, energy harvesting, and storage capabilities. Fabrics from such yarns could provide electrodes for high performance batteries, supercapacitors, and fuel cells that might be imbedded in vehicle shells. Despite important advances, critical problems remain: (1) most multifunctional materials are unspinnable using known technologies, (2) nanopowder and nanofiber functionality often degrades when accessible surface area decreases during processing, and (3) coating nanoparticles or nanofibers on yarns after yarn spinning can severely decrease loading levels and durability.
A generically applicable method is needed for configuring functional nanoparticles, nanofibers, and nanoribbons as the major component of weavable yarns that can perform, for example, as superconductors; battery electrodes; ferromagnets; catalytic convertors; carriers of biological and biopharmaceutical materials; photocatalysts and photosensitizers for photovoltaic cells and photoelectrolysis cells for hydrogen production; hydrogen storage containers; and active oxygen generators for self-cleaning and destruction of biological threats.
A problem hindering the applications of these powder materials is the need for methods for converting these powder (or nanoparticles or nanofibers) into yarns with ultra-high loading of the powder component to effectively utilize the properties of the powder materials. Solid-state-spun carbon nanotube (CNT) sheet as described in U.S. Patent Appl. Publ. No. 2008/0170982, published Jul. 17, 2008 (“the '982 application”), is a novel aerogel material that can support load many times of its own mass and be easily converted into yarns or other shaped articles.
Present invention embodiments provide a novel approach that convert up to 99 weight percent of one or more other functional materials into yarns using twist-based spinning of carbon nanotube sheets. CNT sheets of multiwalled nanotubes (MWNTs), few walled nanotubes (FWNTs), or single walled nanotubes (SWNTs) are used as a platform (providing the mechanical support) for collecting and confining the particle materials, forming a bilayered sheet structure. Then the bilayered sheet ribbon is scrolled into a biscrolled yarn, which is designated the guest@host. The biscrolling method is capable of incorporating large amount of other materials onto CNT sheet, achieving ultra-high loading of the particle materials and maintaining the grain size of the material. As a result, the properties of the biscrolled yarns predominantly come from the deposited guest component other than from CNT sheet. For example, biscrolled yarns have been demonstrated as superconductors; battery electrodes; supercapacitors; carriers of biological and biopharmaceutical materials; photocatalysts for self-cleaning textiles, etc.